Environmental test chamber and a carrier for use therein

ABSTRACT

One aspect of the present invention is a system of fabricating a barrier wall between the testing and tester volumes of an environmental test chamber. This aspect may use a plurality of pallets adapted to receive a device under test and a testing apparatus, a framework adapted to receive a plurality of pallets, and a plurality of insulation bricks associated with the plurality of pallets. The insulation bricks may be adapted such that they can cooperate to form an insulating barrier between the device under test and the testing apparatus.

RELATED APPLICATIONS

[0001] This application is a divisional application of U.S. applicationSer. No. 09/631,055, filed on Aug. 1, 2000, and which claims priorityfrom Provisional Application No. 60/146,812, filed Aug. 2, 1999;Provisional Application No. 60/146,988, filed Aug. 3, 1999; ProvisionalApplication No. 60/158,280, filed Oct. 7, 1999; and ProvisionalApplication No. 60/170,939, filed Dec. 15, 1999.

TECHNICAL FIELD

[0002] This invention generally relates to environmental test chambersand apparatuses for use therein. More particularly, the presentinvention relates to a hard drive carrier, suitable for use in anenvironmental test chamber, having improved flexibility, mechanicalstability, enhanced maintainability, and thermal uniformity. The presentinvention also relates to a barrier wall, and a method of constructionthereof, for isolating a test area from a pseudo-ambient area in anenvironmental test chamber. In addition, the present invention relatesto an environmental test chamber suitable for individual or small batchtesting.

BACKGROUND

[0003] Computer hard drives are usually subjected to a “burn in” testingprocedure conducted in an environmentally controlled test chamber. Thesechambers are designed to isolate the drive from vibrations whileapplying controlled temperature and humidity changes so that the drivemanufacturer can obtain accurate test results.

[0004] Computer hard drives are also usually subjected to thermaltesting or environmental conditioning testing during the design andprototyping phases of the manufacturing process. This testing, alsoknown as “final verification” testing, is also typically conducted inlarge environmental test chambers. The manufacturer selects thehumidity, test temperature, and airflow inside the test chamber so thatit simulates the thermal stress range of conditions that the deviceunder test is realistically expected to “see” in its useful life.Alternatively, the humidity, test temperature, and airflow may beselected to be some multiple of the worst expected conditions. Thesetests can provide a valuable tool to verify product quality andreliability.

[0005] To optimize test time during burn-in and during finalverification testing, the disk drive should be heated or cooled at adefined rate until the specific desired test temperature is reachedwhile applying specified humidity. Accordingly, it is important tomaintain a specific airflow over the drive during this phase to ensurethat temperature gradients within the drive are typical of the end useenvironment. The airflow through the test chamber must also besufficient to ensure a consistent humidity and temperature variancethroughout the chamber while dissipating the heat generated during thetests by the operating device (typically about thirty watts per a diskdrive), but not at a level at which excessive localized cooling wouldfail to simulate the final operational environment of the devices undertest.

[0006] Conventional environmental test chambers consist of one or twochambers. One chamber provides a controlled environmental space for theitems under test (the “testing chamber”), and is designed to provideheat and cool large numbers of disk drives, typically about 120 drivesat a time. There is generally no feedback control from the drives, thecontrol of the overall chamber temperature being the preferred mode ofoperation. Accordingly, significant temperature variations can and dooccur within the testing chamber, which result in different temperaturesfor drives at different locations. Another problem with conventionalenvironmental test chambers is that all of the files in the chamber areheated/cooled together. Thus, these systems are inherently designed forbatch processing.

[0007] The second “tester” chamber, if included, typically provides aspace for the tester hardware (in single chamber devices, the testerhardware is simply left out in the ambient air). The divider between thetesting and tester chambers has customarily been a solid metal wall,with insulated electrical or other “as-needed” connections made viapermanent holes in the wall. This solid metal wall severely limits theflexibility of applications and makes any alteration to accommodatedifferent applications a time consuming and expensive process. The solidmetal wall also allows significant heat transfer between the twochambers.

[0008] The drives are typically held in a fixture or a carrier whilethey undergo the bum-in or final verification testing procedures. Oneproblem with conventional fixtures or carriers is that they are prone totransferring mechanical vibrations to the drive under test. Conventionalholders or fixtures also fail to provide good air circulation around thedrive, contributing to thermal gradients of as much as thirty degreesCelsius. Both of these conditions are undesirable because they add noiseto the test results and generally reduce the utility of theenvironmental test chamber.

[0009] Another problem with current carrier designs is that they lack“user friendliness.” These designs typically use a “swing type” or “barndoor” latch that requires a large rotational motion to engage ordisengage the point clamping site with the drive. These latchingmechanisms also do not provide clear access to both ends of the drivewhen the latch is open. These problems can interfere with cableconnection and arrangement.

[0010] Yet another problem with current carrier designs is that they arerelatively expensive because they require a large amount of rawmaterials and a large number of parts. This problem is compoundedbecause conventional carrier designs are custom designed for a singleuse. For example, carriers built to test 3.5″ disk drives could not beused with 2.5″ drives. These problems increase the manufacturing andassembly cost of the carrier. Lack of flexibility is also a problem infor users who need to test a variety of devices, such as small batchmanufacturers and research facilities.

[0011] Ideally, an environmental testing chamber and carrier testingstation should individually subject each device under test to itsrequired environment, should allow for accurate and precise control ofthe environment, and should allow the devices under test to beloaded/unloaded individually for a continuous flow of products throughthe testing station. This ideal, however, must be weighed against itscost of implementation.

[0012] Clearly, there is a need for more flexible environmental testchamber and hard drive carrier capable of accommodating differentapplications. There is also a need for a simple and inexpensive harddrive carrier that reduces vibration and improves airflow around thedrive. In addition, there is a need for a more user friendly hard drivecarrier that simplifies clamping/unclamping and that provides clearaccess to the ends of the drive at all times.

SUMMARY

[0013] The present invention provides an environmental test chamber anda carrier capable of accommodating different devices under test. Oneaspect of the present invention includes the concept of designing“pallets” to carry components from both the tester and tested device.These pallets may include “bricks” that each form a portion of thebarrier wall between the test environment and tester space. This brickand pallet system provides for easy construction of a thermal barrierand permits great flexibility and versatility in overall design.

[0014] Another aspect of the present invention is a system offabricating a barrier wall between the testing and tester volumes of anenvironmental test chamber. One embodiment of this system comprises aplurality of pallets adapted to receive a device under test and atesting apparatus, a framework adapted to receive the plurality ofpallets in a manner permitting a balance between a maximized number ofpallets and obtaining suitable airflow and temperature uniformity in thetest volume, and a plurality of insulation bricks associated with theplurality of pallets. The insulation bricks cooperate to form aninsulating barrier between the device under test and the testingapparatus. The insulation bricks also cooperate to form a plenum capableof being purged by an appropriate heated purge gas flow.

[0015] Yet another aspect of the present invention is an environmentaltest chamber suitable for individual or small batch testing. Oneembodiment comprises a test volume having an inlet; an air deliverysystem adapted to deliver a flow of air to the inlet; and a drawer,received in the test volume and in pneumatic communication with theinlet. Another test chamber embodiment comprises an air delivery systemadapted to deliver air to a test volume and a plurality of drawersreceived in the test volume and in pneumatic communication with the airdelivery system.

[0016] Still another aspect of the present invention is a method oftesting a plurality of electrical components. This method may comprisethe acts of operably connecting a first electrical component to a firsttest drawer; inserting the first test drawer in a test unit; operablyconnecting a second electrical component to a second test drawer; andinserting the second test drawer in the test unit. The test unit in thisembodiment may either subject the first electrical component and thesecond electrical component to similar environmental conditions or maysimultaneously subject them to different environmental conditions.

[0017] The present invention also provides a simple and inexpensive harddrive carrier that reduces vibrations, improves airflow around thedrive, simplifies clamping/unclamping, and provides clear access to theends of the drive at all times. One embodiment comprises a framedefining a test bed, a clamp pad moveably connected to the frame, a camoperably connected to the clamp pad and adapted to actuate the clamp padinto operable engagement with a hard drive. Some embodiments may alsocomprise an electrical assembly attached to the frame, the electricalassembly being adapted to communicate signals to and from the harddrive. The carrier may also have a first side member and a second sidemember that allow the same carrier to receive and releasibly hold both2.5 inch drives and 3.5 inch hard drives. The hard drive carrier of thepresent invention is particularly suitable for use with theenvironmental test chamber.

[0018] Another aspect of the invention is a carrier apparatus adaptedfor testing different sized devices under test. One embodiment comprisesa first test bed adapted for operable connection with a first deviceunder test; and a second test bed adapted for operable connection with asecond device under test; wherein the first device under test is largerthan the second device under test. Another embodiment comprises a frame;and a clamp operably attached to the frame and adapted to selectivelyhold a first device under test and a second device under test; whereinthe first device under test is larger than the second device under test.In these embodiments, the first device under test may be a 3.5 inch harddrive and the second device under test may be a 2.5 inch hard drive.

[0019] One feature and advantage of the present invention is that itprovides a dual chamber environmental test chamber system that is easilyadapted for use with different devices under test. Another feature andadvantage is an improved carrier having reduced mass, increasedstiffness, and greater omni directional airflow around the drive. Thiscarrier also provides a simple pull/push or pull/push/twist motion tounclamp, to eject, and to prepare to reclamp another drive for test. Inaddition, the carrier provides clear access to the ends of the drive atall time, thus simplifying cable connections. Yet another feature andadvantage is that the present invention provides a practical,implementable, multi-drive test chamber testing system and design thatprovides improved uniformity of temperature control, environmentalcondition variation throughout the chamber by design, product testingflexibility, and capability for small batch and/or single “unit”testing. These and other features, aspects, and advantages will becomebetter understood with reference to the following description, appendedclaims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a perspective view of one carrier embodiment showing thetop, right, and front faces.

[0021]FIG. 2A is an exploded view of two a clamping and releasemechanism embodiments

[0022]FIG. 2B is a detailed view of an alternate clamping and releasemechanisms.

[0023]FIG. 3 is an isometric view of a carrier embodiment adapted toreceive multiple drive sizes.

[0024]FIG. 4 is a perspective view of one embodiment of the presentinvention showing a hard drive being inserted into the test bed and ahandle in a “home” (load/unload) position.

[0025]FIG. 5 is a perspective view of one embodiment of the presentinvention showing a hard drive fully inserted into the test bed and thehandle in a “clamping” position.

[0026]FIG. 6 is a perspective view of an environmental test chamberpallet embodiment showing the top and right sides.

[0027]FIG. 7 is a bottom view of an environmental test chamber palletembodiment of FIG. 6.

[0028]FIG. 8 is a perspective view of an environmental test chamberframe embodiment containing one pallet.

[0029]FIG. 9 is a front view of an environmental test chamber frameembodiment containing a plurality of pallets.

[0030]FIG. 10 is a perspective rear view of an environmental testchamber frame containing a plurality of pallets and a test interfacedevice.

[0031] FIGS. 11A-11C are detailed top, front, and side plan views of anenvironmental chamber brick.

[0032]FIG. 12 is an isometric view of a carrier drawer embodiment foruse with the dual plenum temperature control system.

[0033]FIG. 13 is an isometric view of an environmental test chamberembodiment having a dual plenum temperature control system.

[0034]FIG. 14 is an isometric view of a single plenum temperaturecontrol system.

[0035]FIG. 15 schematically illustrates a multizone dual ductembodiment.

[0036]FIG. 16 schematically illustrates a multizone thermal-reheatembodiment.

[0037]FIG. 17 schematically illustrates an alternate variable-air-volumesystem.

[0038]FIG. 18 is an isometric view of a environmental test chamberhaving a plurality of drawers.

[0039]FIG. 19 is an elevational side view of an environmental testchamber frame embodiment.

DETAILED DESCRIPTION

[0040] The accompanying figures and this description depict and describeembodiments of the present invention, and features, aspects, andcomponents thereof. With regard to means for fastening, mounting,attaching or connecting the components of the present invention to formthe mechanism as a whole, unless specifically described otherwise, suchmeans are intended to encompass conventional fasteners such as machinescrews, nut and bolt connectors, machine threaded connectors, snaprings, screw clamps, rivets, nuts and bolts, toggles, pins and the like.Components may also be connected by welding, adhesives, friction fittingor deformation, if appropriate. Electrical connections or positionsensing components may be made using appropriate electrical componentsand connection methods, including conventional components andconnectors. Unless specifically otherwise disclosed or taught, materialsfor making components of the present invention are selected fromappropriate materials such as metal, metallic alloys, fibers, plasticsand the like, and appropriate manufacturing or production methodsincluding casting, extruding, molding and machining may be used. Inaddition, any references to front and back, right and left, top andbottom and upper and lower are intended for convenience of description,not to limit the present invention or its components to any onepositional or spacial orientation.

I. Hard Drive Carrier

[0041]FIG. 1 is a perspective view of the top, right, and front sides ofone carrier embodiment 10. The carrier 10 includes a frame 12, aclamping mechanism 14, and a connector bar 16. The frame 12 comprises an“L” shaped right side frame member (“right side bar”) 18, a left sideframe member (“left side bar”) 20 that is generally parallel to andcoplanar with the right side bar 18, and a plurality of generallytransverse cross members (“cross bars”) 24 that cooperate with the rightside bar 18 and the left side bar 20 to define a rectangular test bed26. The clamping mechanism 14 in this embodiment comprises a cylindricaloperating rod 30, a linear cam 32, a linear return spring 34, a clamppad 36, an ejection lever 37, an ejection bumper 38, a non-interferinghandle 40, and a hinge 42. The connector bar or module 16 comprises avariety of electrical connections, such as a power supply port 50, anI/O port 52, and a configureable jumper port 53.

[0042] In operation, the user may first eject a previously tested drive(the “old drive,” not shown) by pulling the handle 40 outward, away fromthe frame 12. This pulling of the handle 40: (i) causes the clamp pad 36to move away from and out of engagement with the drive's right sidesurface, which frees the drive; and (ii) causes the ejection lever 37 topivot inwardly around the hinge 42, toward the old drive's rear surface,which causes the ejection bumper 38 to first contact and then push theold drive out of engagement with the connector bar 16. The handle 40 maynow be released, coming to rest in a position where the clamp pad 36 isin a withdrawn position. That is, the operating rod 30, with its linearcam 32, automatically returns to an intermediate position (“home”)determined by the maximum extension of the return spring 34. The olddrive can now be removed and replaced with the next drive to be tested(a “new drive,” not shown). The new drive should be inserted into testbed 26 with sufficient force so that it engages the connector bar 16,thus electrically connecting the new drive's electrical ports to thecorresponding ports on the connector bar 16. The handle 40 is thenpushed toward the frame 12 into a clamping position, which causes theclamp pad 36 to engage and to lock the new drive in the test bed 26.

[0043] The frame 12 in some embodiments comprises a plurality of crossmembers 24. These cross members 24 are designed to maximize thecarrier's stiffness, yet allow for excellent omni-directional air flow.In some embodiments of the present invention, the cross members 24 maybe a combination of beams having “U” shaped cross sections, “T” shapedcross sections, and/or rectangular cross sections. These embodiments aredesirable because the cross members 24 define four air flow apertures54. These apertures 54 allow temperature and humidity controlled air toflow around the bottom and side surfaces of the drive during a test.Embodiments having “U” and “T” shaped cross sections may be particularlydesirable because they can provide greater stiffness than a rectangularcross section of similar weight. This allows the manufacturer to useless material, which reduces their cost of manufacturing, reduces thephysical workload involved in a test chamber operation, and increasesthe size of the apertures 54. Some embodiments may also include one ormore diagonal cross members 24 (not shown) that further increase thecarrier's stiffness.

[0044] In some embodiments, the cross members 24 may also define foursupports or legs 56. These supports 56 are desirable because theyfurther enhance air flow across the bottom surface of the drive, whichhelps to reduce thermal gradients and to increase heat transfer. Thesesupports 56 should be sufficiently strong to hold the combined weight ofthe drive and the carrier 10 and should be relatively wear resistant.However, embodiments without these supports 56 are also within the scopeof this invention.

[0045] The frame 12 may be made from any material with relatively goodstiffness. One suitable material is cold rolled steel. This material isdesirable because it is relatively inexpensive, is easy to machine, anddoes not outgas. However, other materials are within the scope of thepresent invention. These include, without being limited to, grey castiron, hot rolled steel, aluminum, polyethylene, polyvinyl chloride.Dissipative plastics may also be desirable because they are lightweight,relatively inexpensive, and help to further isolate the device undertest from vibrations.

[0046] The handle 40 in this embodiment of the present invention has agenerally vertical orientation and is designed so that it does notinterfere with access to the front of the hard disk drive. This handle40 embodiment is desirable because it allows for easier connection andarrangement of cables. This handle 40 embodiment is also desirablebecause it provides a relatively large opening 41 without interferingwith drive insertion and removal. However, other handle 40configurations, orientations, and positions are within the scope of thisinvention. This specifically includes, without being limited to, ahandle 40 specially adapted for automated or robotic handling.

[0047] The clamp pad 36 in this embodiment has a relatively largeclamping surface 46, which helps to reduce the potential of mechanicalmotion of the drive relative to the frame 12. The clamping pad 36 may bealso fabricated from a resilient vibration damping material or may havea strip 47 of this material attached to the clamping surface 46. Onesuitable vibration damping material is manufactured by Aero E.A.R.Specialty Composites with a part number of C-1002-06 PSA. Theseembodiments are desirable because the vibration damping material reducestest noise, thus improving the test results. However, clamping pads 36made from other materials and/or without the vibration damping strip 47are within the scope of this invention.

[0048] The clamping mechanism 14 in some embodiments may include arotatable joint (not shown), such as an eye bearing, that allows theclamp pad 36 to engage a drive of the drive's orientation (i.e., allowsthe clamp pad 36 to provide clamping force in a 180 degree range). Theseembodiments are desirable because they automatically allow the carrier10 to hold non-rectangular devices under test.

[0049] The drive ejection bumper 38 is designed and located to provide acompliant, yet firm, contact with a wide variety of drives so that itcan facilitate their removal from the carrier 10. One suitable materialis a solid, but relatively compliant, elastomeric material, such asrubber. However, other materials and designs, such as a foamed polymerbumper or an air filled bumper, are within the scope of this invention.

[0050] The connector bar 16 in some embodiments may contain a singleport or a plurality of ports 50, 52 and 53 that are designed to engagecorresponding connector port(s) located on the drive. These ports 50,52, and 53 provide power to the drive and could transmit information toand from the drive.

[0051] The connector bar 16 in some embodiments is removably attached tothe frame 12 by suitable means, such as a groove 70 designed to accept aportion of the connector bar 16 below fingers 72 (FIG. 2A). These“modular” connector bars 16 are desirable because the carrier 10 may bequickly configured to engage drive types and models that use differentbus interfaces, such as IDE, PCI, ATA, or SCSI. That is, users caneasily attach different, interchangeable connector bars 16 to the frame12 whenever the user needs to test drives having a particular interface.Despite this advantage, however, connector bars 16 that are permanentlyattached to the frame 12 are also within the scope of this invention.

[0052] The right side bar 18 and the left side bar 20 in this embodimentinclude a pressure strip 44 of metal-covered vibration damping material.One suitable pressure strip 44 is manufactured by Aero E.A.R. SpecialtyComposites with a part number of SB-40-ALPSA. This pressure strip 44 isdesirable because it provides good wear resistance and reducesvibrations. However, carriers 10 without this pressure strip 44 or witha pressure strip 44 made from other materials capable of dampingvibration and resisting wear are within the scope of this invention.

[0053]FIG. 2A is an expanded view showing a first embodiment of theclamping mechanism 14. FIG. 2A comprises an operating rod 30 havinglarge diameter section 59 and a grooved section 60 that combine to formthe linear cam 32. The diameter of the large diameter section 59 isdesigned such that the operating rod 30 can slide freely through a hole62 in the clamping pad 36. FIG. 2A also shows an actuating spring 64 anda hinge pin 66.

[0054] In operation, the grooved section 60 is aligned with the hole 62when the operating rod 30 is in a fully inserted or “clamping” position.In this position, there is sufficient space between the operating rod 30and the hole 62 such that the actuating spring 64 can pivot the clampingpad 36 around the hinge pin 66 and into engagement with the hard drive.That is, the actuating spring 64 can bias the clamping pad 36 againstthe hard drive when the grooved section 60 is laterally aligned with thehole 62. Sliding the operating rod 30 out of the “clamping position”laterally aligns the wide diameter portion 59 of the operating rod 30with the hole 62. In this position, the wide diameter section 59 of theoperating rod 30 engages the interior surface of hole 62 and preventsthe actuating spring 64 from biasing the clamping pad 36 against thedrive. That is, the operating rod 30 prevents the clamping pad 36 fromengaging the drive whenever the grooved section 60 is not aligned withthe hole 62.

[0055] The operating rod 30 in this embodiment also comprises a flatsection 80 that is adapted to slide freely through a slot 82 in theejection lever 37. A pin 68 fits into a corresponding hole 69 in theflat section 80. Pulling the operating rod 30 from the clamping positionto a partially inserted or “home” position causes the flat section 80 tolaterally slide through the slot 82. This, in turn, causes the pin 68 toengage a back face 74 of the ejection lever 37. Continuing to pull theoperating rod 30 from the home position to a substantially withdrawn or“ejection” position causes the pin 68 to exert a force against the backface 74 of the ejection lever 37. This force pivots the ejection lever37 around the hinge 42 in a clockwise direction (as depicted in FIG.2A), which, in turn, biases the ejection bumper 38 against the drive.The force from the ejection bumper 38 pushes the drive out of engagementwith the connector bar 16. Thus, pulling the operating rod 30 from theclamping position to the ejection position releases the clamp and biasesthe drive away from the connector bar 16.

[0056] Moving the operating rod 30 from the home position to theejection position also causes a flange 90 on the ejection lever 37 tocompress the return spring 34 against the frame 12. When the operatorreleases the handle 40, the return spring 34 produces a force thatpivots the ejection lever 37 around the hinge 42 in a counterclockwisedirection (as depicted in FIG. 2A). The ejection lever 37, in turn,biases the operating rod 30 from the ejection position to the homeposition.

[0057] The flange 90 is designed to slide in a slot 91 between two stops92 and 94. The front stop 92 prevents the operating rod from beingpulled too far out of the frame. The rear stop 94 is positioned so thatit engages the flange 90 when the operating rod 30 returns to the homeposition from the ejecting position. This prevents the ejection lever 37and the return spring 34 from exerting force on the operating rod 30between the home position and the clamping position. That is, the stop94 isolates the operating rod 30 from the return spring 34 between thehome position and the clamping position. After the flange 90 hits thestop 94, the operating rod 30 may continue to be pushed through the slot82 from the home position to the clamping position.

[0058] In a second embodiment clamping mechanism embodiment, theoperating rod 30 may also be contoured along its length to form thelinear cam 32. In this embodiment, the sections having a greaterdiameter may force the clamp pad 36 to move “inward” into the test bedand into contact with the hard disk drive. The portions of the operatingrod having a smaller diameter may allow the clamp pad 36 to move“outward,” which releases the hard drive. The greater diameter sectionsin these embodiments are positioned along the length of the operatingrod 30 such that the clamp pad 36 is forced to engage the drive when thehandle 40 is in the “pushed in” or “clamping” position. The smallerdiameter sections are positioned along the length of the operating rod30 such that the clamp pad 36 can release the hard disk drive when thehandle 40 is in the “home” and “ejection” positions.

[0059] The return spring 34 may also be used in the second embodiment toactuate the handle 40 from an “ejection” position to a “home” position.It is desirable, however, that the return spring 34 be configured sothat it does not disengage the clamp pad 36 from the drive. In someembodiments, this may be accomplished by designing the spring's“neutral” position to correspond to the handle's “clamping” position. Itis also desirable that the chosen spring constant be low enough, or thatthe spring 34 be counter-balanced by a second spring (not shown), so asto prevent the return spring 34 from actuating the operating rod 30 intothose positions where the greater diameter sections engage the clamp pad36. Other springs 34 and mechanisms that are capable of actuating thehandle 40 from the “withdrawn” position to the “home” position and thatdo not disengage the clamping mechanism 14 during use are also withinthe scope of this invention.

[0060] One advantage of these two carrier 10 embodiments is that theloading, clamping, and ejection mechanisms are all operated by one rodusing a simple push/pull motion. This simple push/pull operation of theclamping mechanism 14 may minimize the risk of repetitive motionconditions, such a carpal tunnel syndrome, when compared to therotational sweep clamping mechanisms found in conventional industrydesigns.

[0061]FIG. 2B shows a third cam mechanism embodiment 14 a that ispartially actuated using rotational motion, which may be desirable foruse with robotic loading/unloading devices. The machined portions 60 aof rod 30 in these embodiments act as a rotary cam, rather than a linearcam. That is, the machined area 60 a will have a large diameter arc anda small diameter arc. Rotating the handle 40 by about ninety degrees ineither the clockwise or counterclockwise direction will cause the largediameter arc to alternately engage and disengage the interior surface ofthe hole 62, which, in turn, will latch and unlatch the clampingmechanism 36. Those skilled in the art will recognize that embodimentsusing this rotational cam mechanism 14 a may replace the flat section 80with a round finger 80 a. This finger 80 a, like the flat section 80,should be sized to fit into the slot 82 and should have a hole 69capable of receiving the pin 68.

[0062]FIG. 3 is an isometric view of a carrier embodiment 300 adapted toreceive and test both 2.5″ and 3.5″ hard disk drives. This carrierembodiment 300 includes a second, intermediate L-shaped bar 302 that isgenerally parallel with, but vertically offset (“recessed”) from, theright side bar 18 and the left side bar 20. The intermediate side bar302 in this embodiment has a generally vertical side surface 304, apressure strip 306 adhesively attached to the generally vertical sidesurface 304, a top surface 308, a rear locator surface 309, and agenerally horizontal or slightly inclined bottom surface 310. Thecarrier 300 also comprises three crossbars 24 having an angled notch 320that generally extends between the intermediate bar 302 and the rightside bar 20. The angled bottom surface 310, the angled notch 320, andthe right side bar 20 cooperate to define a second rectangular test bed312. The carrier embodiment 300 in FIG. 3 may use either the linearlatch system or the rotary latch system described with reference toFIGS. 2A-2B.

[0063] In operation, when the carrier 300 is used with 3.5″ drives, itoperates similar to the carrier embodiment 10 described with referenceto FIGS. 1-2 and 4-5. More specifically, the 3.5″ drive sits in thefirst rectangular test bed 26 in a generally horizontal position and isheld in place by the left side bar 18 and the right side bar 20. Becausethe top surface 308 of the intermediate bar 302 is coplanar with orbelow the horizontal surface 314 of the left side bar 18, theintermediate bar 302 does not affect the insertion, testing, or removalof a 3.5″ drive. 2.5″ drives are inserted into the second rectangulartest bed 312, between the intermediate side bar 302, the right side bar20, and the rear locator surface 309. Because the intermediate side bar302 is recessed below the left side bar 18, the 2.5″ drive will sit inthe second rectangular test bed 312 at an acute angle to the horizontal.That is, the 2.5″ drive will rest in and be aligned with the notch 310.Actuating the clamping mechanism causes the clamp pad 36 to pivot aroundthe rotatable joint (not shown) and to engage the side of the drive,which clamps the drive in the inclined position.

[0064] The carrier embodiments in FIGS. 1-5 offer many advantages overthe art. These advantages include excellent vibration reduction, minimalairflow restriction, and single cam operation (i.e., clamp, probe andlatch). Some carrier embodiments also: (i) allow for both automated andmanual loading; (ii) can switch rapidly between different drive sizes;and (iii) can switch rapidly between different I/O standards.

II. Modular Pallets

[0065] Another aspect of the present invention is the use of a “buildingblock” approach to eliminate the limitations associated with the“classic” methods of constructing environmental chambers and to providean environmental test chamber that is both flexible and easy toassemble.

[0066]FIG. 6 shows a modular “carrier pallet” embodiment 100. Thesepallets 100 are adapted to fit into a front frame 111 a and a rear frame111 b that define a plurality of interior receiving slots 106 a andexterior receiving slots 106 b (see FIGS. 8, 9, and 10). Each pallet 100comprises an insulating/air plenum brick 104 connected to a base plate105 by one or more bolts 107. The brick 104 in this embodiment defines atesting space (A), a wall space (B), and a tester space (C). The testspace (A) is designed to accommodate a fixture for holding the deviceunder test, such as the holding fixture 10 or 300, and to allowconnection to a test driving electronic package 103 via flat cable(s)102 (FIG. 7). The tester space (C) is likewise designed to allow easymounting of, and connection to, the tester driving components 103. Thewall space (B) is designed to minimize the quantity of metal and otherconductive materials, thus minimizing thermal transfer between A & C,commiserate with maintaining appropriate rigidity and mechanicalintegrity of the entire pallet.

[0067] In operation, when multiple loaded pallets 100 are inserted intoslots 106, the sides of the bricks 104 seal against each other andagainst the walls of the test chamber. Thus, as shown in FIG. 19, thebricks 104 in the different pallets cooperate to form a completeinsulating barrier (“wall”) between the devices under test and the testdriver components. That is, each brick 104 in an interior slot 106 awill seal against the bricks 104 on the pallet 100 immediately above it,below it, to its left, and to its right (i.e., its “neighboringbricks”). Each brick 104 in an exterior slot 106 b will seal against theside of the environmental test chamber and three neighbor bricks 104.Users will continue to fill the slots 106 until the entire wall iscomplete.

[0068] In some embodiments, the wall may be completely formed using thepallets 100 depicted in FIG. 6. In other embodiments, the wall may bepartially formed using these pallets 100 and completed by the user of“filler pallets” 120 similar to those shown in FIGS. 6-9, but withoutthe device under test or the electronic testing package 103 (see FIGS.9-10 and 19). These filler pallets allow a drive manufacturer to testfewer devices at a time than would be necessary to complete the wall.That is, the filler pallets 120 may substitute for “standard” pallets,thereby allowing the user to test an arbitrary number of devices in onebatch. These filler pallets 120 may be particularly desirable for use inthe exterior slots 106 b to further isolate the devices under test fromenvironmental noise.

[0069] The insulating/air plenum brick 104 embodiment in FIG. 6 is about3″ thick, 3″ high and 6″ long, fabricated from a suitable lightweightinsulating material, such as expanded polystyrene foam (see also FIGS.11A-C). Polystyrene foam is desirable for this application because it islightweight, relatively durable, and inexpensive. However, otherinsulating materials are within the scope of the present invention.These include, without being limited to, polyethylene foam, urethanefoam, ethylene vinyl acetate (“EVA”) foam, asbestos, cork and otherwoods, organic bonded glass fibers, foam rubber, sponge rubber, andmetallic foil laminates.

[0070] The two ends and top of the bricks 104 in this embodiment have apair of strips of sealing material, such as a nylon “hook and loop”material 108 having the“loop” strips, near their outer edges. Thesestrips are desirable because they form a seal or diffusion barrierbetween the testing space (A) and the tester space (C). The bottom ofthe brick 104 may have a similarly placed pair of seals 109 fabricatedfrom a compliant sealing material capable of sealing between the flatcables 102, such as an ethylene propylene diene monomer (“EPDM”) spongerubber available from McMaster Carr of Chicago, Ill. Although EPDM isdesirable for the bottom seal 109 because it is very resistant tochemicals, can withstand high temperatures for extended periods, andremains stable for long periods of time, other sealing materials arewithin the scope of this invention.

[0071] The bricks 104 in this embodiment have a groove 110 (see FIGS. 7,11A-11C, and 19) of about 1″ wide by ⅜″ deep cut into their sidesurfaces. The grooves 110 on each brick cooperate with those on theneighboring bricks and with the walls of the test chamber to provide aplenum network for purge air. Pressurizing these air plenums with anappropriate gas, such as warm dry air, places the wall space (B) underpositive pressure relative to either the test side A or the electroniccontrol side C. This positive pressure prevents to prevent air from thetesting space (A) and the tester space (C) from crossing the wall space(B), which in turn, helps both sides or chambers to be maintained underindependent conditions of temperature and humidity.

[0072] One advantage of the modular pallet 100 is that the correspondingenvironmental test chamber can be quickly and inexpensively modified totest different devices. The modular pallet embodiment is also desirablebecause the corresponding environmental test chamber can test differentcombinations of devices at the same time. That is, some of the palletsplaced in the chamber during a particular testing “run” may contain afirst type device under test and others may contain a second type ofdevice under test. The exact percentage of the first type and the secondtype may even be changed between different runs. Flexible manufacturingplants may find this feature particularly useful because they can usethe same test chamber with their entire production.

III. Environmental Test Chamber

[0073] FIGS. 8-10 depict an environmental test chamber embodiment 150.This test chamber embodiment 150 comprises a front frame 111 a and arear frame 111 b that extend between a base plate 114 and a header 116.The frames 111 a and 111 b define the plurality of pallet supportingslots 106, which are arranged in a grid. This test chamber 150 alsocomprises insulating studs 112 that further support the front frame 111a and the rear frame 111 b. The environmental test chamber also includesa main access door 152 and two air handlers 154 (such as that shown FIG.14) capable of delivering air at a desired flow rate, temperature, andhumidity.

[0074] In operation, a user will insert the pallets 100 into the slots106, which then cooperate to form a testing chamber in the rear portionof the chamber 150. The user will then close the main access door 152,thereby forming a tester chamber for the test driver components in thefront portion of the chamber 150. Finally, the user will activate theair handlers 154. The air handlers 154 deliver separate air flows to thetest chamber and the tester chamber, which allows independent control ofthe temperature and humidity in both chambers.

[0075]FIG. 18 depicts an alternate environmental test chamber embodiment202. As will be discussed in more detail below, this test chamberembodiment 202 has a dual plenum air supply system 200 and a pluralityof drawers 250. One drawer 250 is positioned for servicing and changingfixtures and/or cables. The remaining drawers 250 are positioned in atesting or operational position. In addition to the advantages describedabove, this test chamber embodiment 202 is desirable because itprovides: (i) a dual plenum system for supplying hot and coldpressurized mixed air at a controlled temperature gradient or at a fixedtemperature; (ii) the ability to test in small batches, thus decreasingaverage test cycle time; (iii) high uniformity/stability of the targetconditions and fast temperature ramp rates due to its use of a smalltest chamber volume, high air flow, and continuous feedback; (iv) theability to run hot and cold tests can be run simultaneously in anynumber of drawers 250 in embodiments where each drawer, or nest ofdrawers, is fed by an independently controlled mixing plenum system; (v)a substantial reduction of internal temperature gradients provided bythe small volume/tight control operating philosophy; and (vi) a highlycompact, stackable design that can be placed back-to-back with anothertest chamber 202.

A. Small Batch Testing

[0076]FIG. 12 is an isometric view of a drawer 250 that is suitable foruse with the environmental test chamber 202. This drawer embodiment 250comprises four pallets 100, such as those described with reference toFIGS. 6-7, that are permanently mounted on a shelf 252. The pallets 100and the shelf 252 are designed to seal against adjacent drawer(s) 250and/or the interior of the test chamber 202, thereby creating asubstantially sealed testing subchamber 254. Each subchamber 254 has twoinlet orifices 224 in one side wall 256, two outlet orifices 226 in theopposite side wall 258, and its own temperature/humidity/air flow sensor210.

[0077] In operation, a disk drive manufacturer can load four drives ineach drawer 250, through the front of the drawer 250. Air enters theresulting subchamber 254 from the inlet orifices 224, circulates aroundthe four drives, and exits through the outlet orifices 226. Theseembodiments are desirable because each subchamber 254 acts as a separatemini-environmental test chamber, which decreases the test's batch size.That is, the environmental conditions in each subchamber 254 aresubstantially independent of the presence or absence of other drawers250 in the test chamber 202 and substantially independent of theenvironmental conditions in the other drawers 250. This allows themanufacturer to insert one drawer 250 into the test chamber 202, bringthat drawer's subchamber 254 up to the desired testing conditions, andto conduct the desired test—all without having to completely fill theentire chamber 202 with disk drive or filler pallets. Thus, themanufacturer can perform a test on some drives while simultaneouslyloading other drives into another drawer 250. This feature is desirablebecause it can decrease the average amount of time necessary to conductthe tests and because it reduces the mass that must be heated or cooledto preform each test, as only the specific occupied drawers aremaintained at the desired test environment.

[0078] In some embodiments, the inlet orifices 224 admit blended airfrom a single mixing chamber 218 and the outlet orifices 226 allow airto exit to a single return plenum 225. The sensors 210 associated witheach drawer 250 provide a control computer 212 (FIG. 13) with continuoustemperature, humidity, and air flow rate information about thesubchamber 254. The control computer 212, in turn, adjusts the airhandling system to produce optimum uniformity and stability in targettemperatures. In these embodiments, the orifices, plenums, controlsystem, and drawers should be designed produce a small test volume, highair flow, and continuous feedback. This combination will help maximizetemperature uniformity and stability despite the changing operatingconditions in chamber 202.

[0079] In other embodiments, the sensors 210 can be used to individuallycontrol the environmental conditions in each subchamber 254 or in smallgroups of subchambers 254. These embodiments may be desirable becausehot and cold tests can be run simultaneously in any number of drawers250 and because the individual controls will further improve uniformityand stability of the target temperatures.

B. Temperature and Air Flow Rate Control

[0080]FIG. 13 is an isometric view of a dual plenum air systemembodiment 200 suitable for use with the environmental test chamber 202.This air plenum system 200 comprises a cold air supply duct (“cold airplenum”) 204 and a hot air supply duct (“hot air plenum”) 206, both ofwhich are pneumatically connected to a fan or blower 208 by a flowdivider. The hot air plenum 206 has a heating element 209 and can supplyair at any reasonably defined temperature above the desired test chambertemperature. The cold air plenum 204 has a cooling element 214 and cansupply air at any reasonably defined temperature below the desired testchamber temperature. The hot and cold air plenums 204 and 206 supply amixing chamber 218, which mixes and blends the hot and cold air streamsinto a uniform air stream at the target temperature and humidity. Thismixing chamber 218 includes two computer controlled dampers 219 and avariable speed fan or blower 220, and is pneumatically connected to theenvironmental test chamber 254 by the inlet orifices 224 associated witheach drawer 250 (FIG. 12). The outlet orifices 226, in turn, allow airto pass from the testing subchamber 254 into a return plenum 225. Theair plenum system 200 in some embodiments may also include a humidifier227, additional computer controlled baffles or dampers 228, and acomputer control system 212. This control system 212 is operablyconnected to a temperature, humidity, and air flow rate sensor 210located inside the environmental test chamber 254, to the dampers 219and 228, to the variable speed fan 220, and to the humidifier 227, andto the heating 209 and cooling 214 elements.

[0081] In operation, the fan 208 draws air from the return plenum 225and/or the ambient air outside the chamber 254, and forces it into thecold air plenum 204 and the hot air plenum 206. The air entering thecold air plenum 204 passes over the cooling element 214, where it can becooled to a temperature below the desired test chamber temperature.Those skilled in the art will recognize that this can cause water tocondense out of the air stream, which decreases the air stream'shumidity ratio. The air stream entering the hot air plenum 206 similarlypasses over the heating element 209 and is heated above the desired testchamber temperature.

[0082] After the air passes through the cold air plenum 204 and the hotair plenum 206, the two air streams are combined and blended together inthe mixing chamber 218. The mixing chamber includes two computercontrolled air dampers 219, one for the cold air plenum 204 and one forthe hot air plenum 206, that are operably connected to the controlsystem 212. The control system 212 can use a signal from thetemperature/humidity sensor 210 to actuate the dampers 219. This, inturn, adjusts the respective flow rates of the hot and cold air streams.The end effect is similar to the mixing faucet on a kitchen sink, onlywith the fluid being air rather than water. In some embodiments, thecontrol system 212 also controls the operation of the humidifier 227(not shown), which allows it to selectively increase the humidity of theblended air stream.

[0083] The fan 220 draws air from the mixing chamber 218 and pushes itthrough the inlet orifices 224, into the environmental test chamber 254.After the air has circulated around the devices under test, it exits thetest chamber 254 through the outlet orifices 224. A damper 228 in thereturn plenum 225 can then either direct the air stream back into thefan 208, vent it to atmosphere, or a combination thereof, depending onwhich choice is the more energy efficient for the desired testconditions.

[0084] The heating element 209 may be any device capable of heating theair stream flowing through the hot air plenum 206. Suitable devicesinclude, without being limited to, an electrical heating element or aheat exchanger connected to supply of hot water or steam. The coolingelement 214 may similarly be any device capable of cooling the airstream flowing through the cold air plenum 204. Suitable devicesinclude, without being limited to, a heat exchanger connected to asupply of chilled water or may be a vapor-compression cyclerefrigeration unit. The temperature/humidity/air flow sensors 210 may beany device, or combination of devices, capable of sensing thetemperature, humidity, and air flow inside the test chamber or chambers.

[0085] The baffles or dampers 219 and 228 can be any device, orcombination of devices, that can control and change the flow rate of airthrough a duct. Computer controlled baffles or dampers 219 and 228 areparticularly desirable because they will allow a user to quickly andeasily change the conditions inside the test chamber 254. However,manually actuated devices 219 and 228 are also within the scope of thepresent invention.

[0086] The air delivery system in FIG. 13 is depicted as verticallysurrounding a cluster of drawers 250 (FIG. 12). These verticalembodiments are desirable because the air delivery system 200 can beeasily built around the test chamber 254 such that the chamber/airdelivery system form a single, integrated unit. However, the airdelivery system 200 could be located at any other angle relative to thedrawers 250 and could feed one drawer 250 or a plurality of drawers 250.

[0087] The control system 212 can be any device or combination ofdevices capable of maintaining the conditions inside the test chamber(s)at or near the target conditions. In some embodiments, the control unit212 is an microprocessor implemented active feedback control system thatuses the signal from the sensors 210 to operate the dampers 219 and 228,the variable speed fan 220, and the humidifier 227. Other suitablecontrollers include, but are not limited to, an analog or digitalfeedback device running an appropriate control algorithm.

[0088] Many variations of the embodiment in FIG. 13 are within the scopeof the present invention. For example, the cooling element 214 may beeliminated. The cold air plenum 204 in this embodiment will then supplyeither ambient\room temperature air or return temperature air to themixing chamber 218, depending on which is more energy efficient for thedesired test conditions. In addition, the present invention may includea flow straightener between the mixing chamber and the inlet orifice224. This flow straightener can be any device capable of reducing oreliminating the turbulence caused by the fan 220. Suitable devicesinclude, but are not limited to, a bank of tubes or honeycomb structurethat forms a plurality of small diameter flow paths. The flowstraightener may be desirable for its potential to reduce vibrationscaused by uneven air flow.

[0089]FIGS. 15, 16 and 17 schematically depict alternate air deliverysystem embodiments suitable for use with the multiple, independentlycontrollable subchambers 254 described with reference to FIGS. 12 and13. Specifically, FIG. 15 depicts a dual duct variable-air-volume(“VAV”) system in which each subchamber 254 has its own mixing chamber218. FIG. 16 depicts a multizone single plenum system with terminalreheat. In this embodiment, all of the air is cooled to a temperaturelow enough to assure dehumidification. The sensor 210 in each subchamber254 is used to control its associated reheat coil 209 to insure that theair entering each subchamber 254 is at the proper temperature andhumidity. FIG. 17 depicts a single plenum VAV system with terminalreheat. Terminal reheat systems like those shown in FIGS. 16 and 17 maybe desirable because they only require a single duct. This feature candecrease the system's initial cost and complexity. Dual duct systemslike that shown in FIG. 15, however, are more energy efficient. Thiswill decrease the system's operating costs.

[0090] One particular embodiment of the present invention incorporatesall three aspects described above designed and operates in a synergisticmanner to produce excellent uniformity of temperature/humidity and airflow on the test side and minimal heat transfer between the test andtester sides due to the excellent thermal insulation provided by thebricks, their framework, the constructed the air plenum system, and thewarm dry air purge pushed into the plenum. In this embodiment, thepallet 100 is fabricated from cold rolled steel, the framework 111 a and111 b is fabricated from cold rolled steel, powder coated; the insulatedstuds 112, the base plate 114 and header 116 are fabricated from a gradeXX paper/phenolic laminate sold under the trade name GAROLITE byMcMaster Carr of Chicago, Ill.; the insulating bricks 104 are fabricatedfrom the RayLite® brand expanded polystyrene produced by DiversiFoamProducts of Rockford, Minn.; the rubber seals are fabricated from EPDMsponge rubber; and the brick 104 top and side closure are fabricatedfrom the “loop” material of nylon “hook and loop” fabric.

[0091] Although the present invention has been described in detail withreference to certain examples thereof, it may be also embodied in otherspecific forms without departing from the essential spirit or attributesthereof. For example, although present invention have generally beendescribed with reference to a computer hard drive, and in particular forenvironmental testing of 3.5 inch and 2.5 inch, disk drives, theprinciples could be extended to controlled environment testing of otherdevices. These include, without being limited to, compact disk (“CD” or“CD-ROM”) drives, digital video disk (“DVD”) drives, tape drives,“cards” for computer peripherals, computer memory chips, integratedcircuit wafers, personal computer devices, consumer electronics, etc.Aspects of the present invention can also be used as an incubator, orthe like, in biological manufacturing processes and testing. Inaddition, the carrier and/or the pallets may include auxiliary fandesigned to improve airflow around the device under test. Therefore, itis desired that the embodiments described herein be considered in allrespects as illustrative, not restrictive, and that reference be made tothe appended claims for determining the scope of the invention.

What is claimed is:
 1. An environmental test chamber, comprising: an airdelivery system adapted to deliver air to a test volume; and a pluralityof drawers received in the test volume and in operable communicationwith the air delivery system.
 2. The apparatus of claim 1 , wherein eachdrawer in the plurality of drawers comprises a subchamber in independentoperable communication with the air delivery system.
 3. An environmentaltest chamber, comprising: a test volume having an inlet; an air deliverysystem adapted to deliver a flow of air to the inlet; and a drawer,received in the test volume and in operable communication with theinlet.
 4. The apparatus of claim 3 , wherein the air is temperaturecontrolled.
 5. The apparatus of claim 3 , wherein the air is humiditycontrolled.
 6. The apparatus of claim 3 , wherein the air deliverysystem comprises a hot supply plenum and a cold supply plenum.
 7. Theapparatus of claim 3 , further comprising: a sensor associated with thedrawer, wherein the sensor is in operable communication with acontroller.
 8. The apparatus of claim 7 , wherein the air deliverysystem comprises a fan controlled by the controller, the fan beingadapted to control the flow of air to the test volume.
 9. The apparatusof claim 7 , wherein: (i) the air delivery system comprises a hot plenumdamper controlled by the controller, the hot plenum damper adapted tocontrol a flow of hot air through a hot supply plenum; and (ii) the airdelivery system comprises a cold plenum damper controlled by thecontroller, the cold plenum damper adapted to control a flow of cold airthrough a cold supply plenum.
 10. The apparatus of claim 7 , wherein theair delivery system comprises a mixing chamber in operable communicationwith the hot supply plenum and the cold supply plenum.
 11. The apparatusof claim 7 , wherein the controller is a feedback controller.
 12. Theapparatus of claim 3 , further comprising a plurality of drawers and aplurality of inlets, wherein each drawer in the plurality of drawers isin independent operable communication with at least one inlet in theplurality of inlets.
 13. The apparatus of claim 12 , further comprisinga plurality of plenums in operable communication with the plurality ofinlets.
 14. The apparatus of claim 13 , wherein each plenum in theplurality of plenums can be operated at different environmentalconditions.
 15. The apparatus of claim 3 , wherein the drawer is adaptedto receive a device under test.
 16. The apparatus of claim 3 , whereinthe drawer is adapted to receive a plurality of devices under test. 17.A method of testing a plurality of electrical components, comprising:operably connecting a first electrical component to a first test drawer;inserting the first test drawer in a test unit; operably connecting asecond electrical component to a second test drawer; and inserting thesecond test drawer in the test unit.
 18. The method of claim 17 ,wherein the test unit subjects the first electrical component and thesecond electrical component to similar environmental conditions.
 19. Themethod of claim 17 , wherein the test unit simultaneously subjects thefirst electrical component to a first environmental condition and thesecond electrical component to a second environmental condition.
 20. Atesting apparatus, comprising: a housing; a plurality of drawersreceived in the housing; an air deliver system adapted to deliver airindividually to each drawer; and a controller to regulate flow of airinto each drawer.
 21. The apparatus of claim 20 , and further comprisinga plurality of sensors, each sensor located within a drawer and each incommunication with the controller.
 22. The apparatus of claim 21 ,wherein the controller regulates temperature in each drawerindependently.